Translucent screen for projection machines



June 5, 1928 1,672,631

E. A. TROEGER TRANSLUGENT SCREEN FOR PROJECTION MACHINES Filed Aug. 21, 1925 ud/bnce anvewto'c Ernesf fl-Traeger.

35x 1 Guam 8 Patented June 5;. 1928" UNITED STATES PATENT "or F les.

mass a. madman, or new rent, N. Y., assIeNon, 51mm ASSIGNMENTS, r0 I rams-Lox narnronr rrc'runn scams cons-cannon.

'TBANSVIIUGENT SCREEN FOR PROJECTION MACHINES.

Application filed August 21,1925. Serial No. 51,5".

This invention relates to screens upon which pictures are projected, and more particularly to a translucent screen which is adapted to be interposed between a. camera and the audience.

It has been proposed to make translucent screens out of various substances includin layers of different materials consisting o raw materials and heterogeneous compounds and mixtures, but these screens have allhad some undesirable properties such as fragility, lack of self-sustaining strength, liability to decomposition by the action of moisture, and absence of proper translucent characteristics required for correct reproduction of an image and softness of light passing there- 'through. An attempt toimprove any one of these characteristics in translucent screens heretofore produced results in seriously affecting another characteristic and in most cases the translucent efiiciency of'the screen. It is, therefore, among the purposes of my invention to produce a translucent screen having such fineness and smoothness of texture or grain'and clearness of color as to very distinctly bring out and show the image, either in natural colors or in black and white, without causin any fatigue to the eyes ofan observer, an at the same time Obtaining a screen in which the undesirable characteristics recited above are-obviated.

Y Another object is to produce a screen ,which will be impervious to the deleterious effects of moisture and have sufiicient firm-' ness and toughness to withstand sagging while in use and yet be so flexible as to permit being rolled as a curtain and for storage purposes when not in use without in way detracting from its translucent cienc lucent' roperties as well. as to be able to soften e lightwhich' passes therethrough .Other' objects and uses of the invention and toward the audience: In obtaining such a screen care must also be exercised in gainmg mechanical properties which will sufiice to withstand at least, ordinary use and exposure without detracting from the high character of translucency desired, and I have discovered that a composition including pure gum rubber, properly treated and tinted, is

admirably adapted to fulfill both light and mechanical requirements.

In preparing the composition for my screen it is necessary to use about ninetyseven per cent of pure gum rubber with about one per cent of oxide of zinc and about two per cent of an aniline dye of a selected color. The proportions of the various ingredients may be varied to some extent without varying the character of the actual product, but I have obtained a satisfactory screen with the proportions'set forth.

These ingredients must be kneaded together very thoroughly, in a manner well known in the art, under proper heat conditions, until a homogeneous dough-like product of uniform texture and tint results. This product is then rolled into sheetsby a calendering machine which may be designed to leave one side smooth and the other side slightly roughened, as, for example, by the impressions resulting from having1 one of rolls covered wit fabric. This roughene surface is positioned, when the screen is read for'use, toward the audienee and it ai s in the light diffusion. Both sides, however, could" be left smooth the calender-in since the character of the'screen itself tends to diffuse the lightand there}? prevent glare. After the sheets are roll t ey are steam-cured and are then ready for'use.

In order to obtain good results I have found that the thickness ofthe sheets should preferably be about fifteen-gauge, but thickneses ranging from ten gau to thirty uge give good results under ifierent conitions.

As well as serving as a necessary medium in the steam-curin process, the zinc oxide is a useful factor w lch aids in making the rubber screen adaptable to make the images stand out and be clearly legible. It also serves, together with the selected aniline dye, to give a. desired tint to the screen and hence to the appearance of the image. The tinted ment are contem screen serves to filter out theharsh colors emitting from the lamp in the projectlng machine, and I have had excellent results in producing a soft and restfullight effect by the use of a blue aniline dye.

. A sheet of rubber produced by the steps hereinbefore stated is tough and flexibleand slightly elastic, chanical-properties which render it suitable for curtain and screen purposes. It is not liable to sag and wrinkle or become distorted under varyin climatic conditions and its elasticity ena les it to be kept taut and smooth at all times. Its excellent translucent properties are dependent upon the prepared material itself, and its mechanical characteristics enable it to be manufactured and used at thicknesses which have not been heretofore attainable.

Changes in duration and manner of treatthe ap ended claims, and I do not wish to be limited to the exact proportions of ingredients specified.

Y of translucent cured rubber materia What I claim is 1. A projection screen comprisi a sheet 2. A projection screen comprising a sheet of translucent cured rubber having a diffuser incorporated therein.

3. A projection screen comprising .a sheet of translucent cured elastic rubber material. 4. A projection screen formed of a sheet ofetranslucentrubber material containing a small percentage of zinc'oxide.

1 5. A pro ectlon screen comprising a sheet of translucent cured rubber as its principal constituent.

6. A projection screen formed, of a sheet of pure gum rubber and also containing a small percentage of zinc oxide.

7. A projection screen formed of a sheet of pure gum rubber and also containing a thereby having inherent melated within the scope of small percentage of zinc oxide and a color-.

ing dye. v

8. A projection screen formed of a sheet oftranslucent pure gum rubber rolled and steam-cured.

9. A projection screen formed of a sheet of material containing approximately 97% pure gum rubber, approximately 1% zinc oxide, and approximately 2% offcoloring e. 10. A projection screen formed of a sheet of material containing approximately 1% zinc oxide and a preponderanceof pure gum rubber.

11. A rojection screen formed of a sheet of material containing approximately 97% pure gum rubber,

the sheet being rolled and steam-cured.

approximately 1% zinc oxide, and approximately 2% coloring dye, v

of material containing approximately 1% zinc oxide and a preponderanceof pure gum rubber, the sheet being rolled and steam cured.

. 13: A projection screen comprising a sheet of translucent cured rubber material of a thickness between ten gauge and thirty gauge.

14.. 'A projectionscreencomprising a sheet of translucent cured rubber material of a thickness of approximately fifteen gauge.

15. A translucent projection screen compri'ng a cured rubber sheet having incorporated therein a diffuser.

16. A projection screen comprising a sheet of trans ucent cured rubber materlal of a thickness between ten gauge and thirty, gauge, and havingincorporated'therein a diffuser.

In testimony whereof I hereto aflixmy signature.

ERNEST A. 'rnonena. 

